This project will evaluate the interaction of components derived from Capnocytophaga bacteria with the immune system. Cell envelope and cytoplasmic material from 3 species of this potential periodontal pathogen has been isolated by our laboratory. This material will be examined for its effects on human peripheral blood lymphocytes in vitro. These evaluations will determine antigenicity, mitogenicity, polyclonal B lymphocyte activation and immunomodulation. The in vivo antigenic significance of these bacterial components will be evaluated by immunoblotting with serum from periodontally diseased and healthy subjects. Differences in immunoblot patterns will be determined by immunostaining with IgG subclass specific antisera which will increase sensitivity. Those bacterial components which have in vitro immunological activity and/or show different immunoblot patterns between healthy and periodontally diseased serum will be further purified and retested. The bacterial components will be further purified by preparative-ultracentrifugation, gel filtration, ion exchange chromatography and preparative elution electrophoresis. Purity will be evaluated by polyacrylamide gel electrophoresis. Evaluation of antibody response patterns to Capnocytophaga by immunoblotting will: 1) identify the important antigens associated with the organism 2) allow rapid differentiation of antibody response patterns in periodontally diseased subjects and 3) help clarify the conflicting reports on the role of Capnocytophaga in periodontal disease. The identification of specific bacterial components which have the potential to alter local host defenses will provide considerable insight into the bacterial etiology and much discussed immunopathology of the periodontal lesion. Purification of these potential virulence factors may facilitate development of monoclonal antibodies which may be used for identification of bacterial components in plaque and diseased gingival tissue. Such technology may lead to development of immunodiagnostic methods for determining active versus stable diseased sites by the presence or absence of a particular bacterial substance. This would be of much benefit in developing patient treatment plans.